In an information processing system, it is a general practice to connect many information processors with an interface such as a network for data communication between them, thereby enhancing the performance and reliability of the information processing system as a whole.
The conventional scheme such as mentioned above includes, for example, the automatic switching of communication between duplicated systems as disclosed in Japanese Non-examined Patent Publication No. 63-44248. According to the disclosed scheme, in the duplicate system composed of a master system and a slave system, each system is provided with a network adapter which connects one of the systems to the network through a selector switch. When switching between systems, a monitor for the duplicate system activates the selector switch for switching from the master system to the slave system.